Method of manufacturing semiconductor device in which bottom surface and side surface of semiconductor substrate are covered with resin protective film

A semiconductor device manufacturing method comprising:

• preparing an assembly having an insulating film formed on one surface of a semiconductor wafer where an integrated circuit is formed, an interconnect formed on the insulating film in such a manner as to be connected to the integrated circuit, an external connection bump electrode formed on the electrode connection pad portion of the interconnect, and a sealing film formed around the external connection bump electrode;
• affixing a support plate to the external connection bump electrode and the sealing film via an a separation layer;
• forming a trench reaching an intermediate position of the thickness of the sealing film on the bottom side of the semiconductor wafer in parts corresponding to a dicing street and both sides thereof;
• forming a resin protective film on the bottom surface of the semiconductor wafer including the inner part of the trench;
• supplying energy from the support plate side onto the separation layer;
• removing off the support plate from the external connection bump electrode and the sealing film;
• and
• cutting the sealing film and the resin protective film in a width smaller than the width of the trench.